The present invention relates to a solar battery with built-in diodes.
The connection structure disclosed in U.S. Pat. No. 6,034,322 is known as a technique for mounting a diode to a solar battery cell. A top view of a conventional solar battery cell with built-in diode is shown in FIG. 9 and a cross-sectional view of the conventional solar battery cell with built-in diode is shown in FIG. 10. To effectively utilize a disc-shaped crystal substrate, a triangular planar diode is mounted at the corner crop provided in the solar battery cell.
In the figure, a solar battery cell 1 has a beveled edge where one corner has been partially removed, and a diode 2 is provided at the same position as the removed edge. In this solar battery cell with built-in diode, a diode connection bracket 3a is respectively connected to a front surface electrode 4 of the solar battery cell 1 and to a front surface electrode 6 of the diode 2, and a diode connection bracket 3b is respectively connected to a rear surface electrode 5 of the solar battery cell 1 and to a rear surface electrode 7 of the diode 2 using a method such as parallel gap welding.
This electrically connects the solar battery cell 1 and the diode 2 in parallel so that damage to the solar battery cell 1 can be prevented even if a reverse voltage is applied to the solar battery cell 1.
Furthermore, although the voltage generated from one solar battery cell differs according to the type of the solar battery cell, it has at the most a range of 0.5 to 3 V. Thus, it is common to obtain a predetermined working voltage by configuring a circuit to connect a plurality of solar battery cells in series. In an ordinary solar battery cell circuit, a plurality of solar battery cells are connected in series by connecting solar battery cell brackets to the front surfaces and the rear surfaces of adjacently positioned solar battery cells.
Therefore, in the conventional solar battery cell with built-in diode, in addition to the solar battery connection bracket for connecting each solar battery cell in series, two diode connection brackets are necessary for connecting the diode 2 in parallel.
Since the diode connection bracket, which has a characteristic shape with a function only to connect the solar battery cell and diode as described above, is used to connect the solar battery cell and the diode in the conventional solar battery cell with built-in diode, the larger number of connection points increases the time required for adding a diode to the solar battery cell, and the reliability decreases.
In particular, the front surface of the solar battery cell is provided with rectangular front surface electrodes near the periphery of the solar battery cell, and making connections, such as through welding, to match the positions of the front surface electrodes is difficult, and the assembly time increases due to the larger number of connection points.
Furthermore, simultaneously connecting the front and rear surfaces of the diode and the front and rear surfaces of the solar battery cell with connection brackets 3a, 3b was difficult. Another concern was the increase in the number of parts and part types and the increase in the cost of materials that resulted from the increase in the number of connection points.
Moreover, the solar battery array has become significantly large so that low efficiency, low cost silicon solar battery cells are not used any longer. As a result, gallium arsenide based solar battery cells of the high efficiency III-V group (of the periodic table) must be considered. Regarding these solar battery cells in terms of initial manufacturing cost, the solar battery cells forming the base are high in cost so that it is necessary to utilize the most active area of the blank cells.
In addition, another problem was that adding an electrode for connection with the diode to the front surface of the solar battery cell decreases the area contributing to power generation so that the amount of generated electricity decreases. The power loss in generated electricity accompanying the addition of electrodes is about 0.1% of the total generated electricity of one 50 mm square solar battery cell (generated electricity of about 1 W). If 100,000 of these solar battery cells are used as a solar battery for mounting in a satellite to generate electricity, a power loss of about 100 W results, which is an amount that cannot be ignored in the supply of power to the satellite.
It is therefore an object of this invention to solve the relevant problems by reducing the increase in manufacturing cost and the drop in reliability accompanying the addition of the diode to the solar battery cell, and by increasing the amount of generated electricity of the solar battery cell through the reduction of the front surface electrode area on the solar battery cell.
The solar battery relating to the present invention comprises planar first and second solar battery cells, a diode connected in parallel with the first solar battery cell, a solar battery connection bracket for connecting a front surface electrode provided on a front surface of the first solar battery cell and a rear surface electrode provided on a rear surface of the second solar battery cell and a front surface electrode provided on a front surface of the diode, and a diode connection bracket for connecting a rear surface electrode provided on a rear surface of the first solar battery cell and a rear surface electrode provided on a rear surface of the diode. The first solar battery cell and the second solar battery cell are planar solar battery cells that are substantially rectangular having four corners, at least one of the corners has a partially removed beveled edge, and the diode is positioned adjacent to the beveled edge in the area of the removed corner.
Furthermore, the solar battery connection bracket has at least one rectangular first connector for connecting the front surface electrode of the first solar battery cell and the rear surface electrode of the second solar battery cell, at least one rectangular second connector for connecting the rear surface electrode of the second solar battery cell and the front surface electrode of the diode, and at least one rectangular third connector for connecting the rear surface electrode of the first solar battery cell and the rear surface electrode of the diode. The first connector, the second connector, and the third connector may be connected on the side opposite to the light receiving surface of the solar battery cell.
Furthermore, the solar battery relating to the present invention comprises planar first and second solar battery cells, a diode connected in parallel with the first solar battery cell, a first solar battery connection bracket for connecting a front surface electrode provided on a front surface of the first solar battery cell and a rear surface electrode provided on a rear surface of the second solar battery cell, a second solar battery connection bracket for connecting the rear surface electrode of the second solar battery cell and a front surface electrode provided on the front surface of the diode, and a diode connection bracket for connecting a rear surface electrode provided on a rear surface of the first solar battery cell and a rear surface electrode provided on a rear surface of the diode. The first solar battery cell and the second solar battery cell are planar solar battery cells that are substantially rectangular having four corners, at least one of the corners has a partially removed beveled edge, and the diode is positioned adjacent to the beveled edge in the area of the removed corner.
Furthermore, the solar battery relating to the present invention is formed by positioning in successive adjacency at least two solar battery cells with built-in diode, which includes planar solar battery cells that are substantially rectangular having four corners with at least one of the corners having a partially removed beveled edge and the diode positioned adjacent to the beveled edge in the area of the removed corner, and in which front surface electrodes provided on front surfaces of the solar battery cell and the diode included in one solar battery cell with built-in diode and rear surface electrodes provided on rear surfaces of the solar battery cell and the diode included in another adjacent solar battery cell with built-in diode are connected by one solar battery connection bracket.
Furthermore, the solar battery cell relating to the present invention is formed by positioning in successive adjacency at least two solar battery cells with built-in diode, which includes planar solar battery cells that are substantially rectangular having four corners with at least one of the corners having a partially removed beveled edge and the diode positioned adjacent to the beveled edge in the area of the removed corner, and in which surface electrodes provided on front surface of the solar battery cell included in one solar battery cell with built-in diode and rear surface electrodes provided on rear surface of the solar battery cell included in another adjacent solar battery cell with built-in diode are connected by a solar battery connection bracket, and a surface electrode provided on the front surface of the diode included in the solar battery cell with built-in diode and rear surface electrodes provided on rear surfaces of the solar battery cell and the diode included in the other adjacent solar battery cell with built-in diode are connected by a diode connection bracket.
Furthermore, the solar battery connection bracket or the diode connection bracket may be made of a material that includes silver.
Furthermore, the front surface electrode or the rear surface electrode of the solar battery cell, or the front surface electrode or the rear surface electrode of the diode may include silver.
Furthermore, the solar battery connection bracket or the diode connection bracket may have a bend for a thermal expansion buffer.
Furthermore, the bends may have a U-shaped structure.
Furthermore, only one of the corners may have a beveled edge.
Furthermore, the beveled edge may be formed from an arc.
Furthermore, the solar battery cell may be cut out from a disc-shaped crystal substrate.